1. Field of the Invention
This invention relates to a scanning array for use in conjunction with personal communication systems (PCS) and, more specifically, to a compact antenna for use in conjunction with mobile communication systems.
2. Brief Description of the Prior Art
In the field of mobile communication, such as, for example, cellular telephone systems which operate generally in the 850 MHz and 1900 MHz frequency regions, it is necessary to provide a multiplicity of antennas throughout the area covered by the system so that a user of the system has access thereto at all locations within the covered area. The quality of communication depends in part upon the gain of the antenna arrays and the number and proximity of antenna arrays to each other within the covered area. Gains in excess of 21 dBli are consistently requested by users. Improved gain is constantly being sought, especially in the 1900 MHz frequency region. The prior art has generally used patch and dipole antennas in a flat or "billboard" style with the "billboard" plane being vertical for this purpose with the antenna elements extending outwardly horizontally or parallel to the ground to provide the proper pattern for these types of antenna elements. Such antenna arrays generally have dimensions of about 3 feet by about 5 feet or more to obtain the required gain.
Two methods of improving access to the system have been to increase the number of antenna arrays in the covered area and/or to increase the gain of the system antenna arrays, this being accomplished by increasing the surface areas of the individual antenna arrays. While an increase in antenna array area does and has improved access to the mobile communication systems, such larger area antenna arrays become increasingly unsightly with increase in size, especially for tower top applications in urban environments where their use can also be subject to adverse zoning requirements. Such larger area antennas also become more subject to wind load effects with increase in exposed area. Such wind load effects also have a deleterious effect on the electrical properties of the antenna. It is therefore apparent that an improved type of antenna system which eliminates or at least minimizes the above noted problems of the prior art is highly desirable.